The present application is directed to bone pins and wires, and, more specifically, to bone pins and wires used to attach a bone fragment to an anchor bone for a healing duration.
Bone pins and wires are characterized by having a relatively small diameter, such as a diameter less than 0.1 inch (2.5 mm). Bone pins which are elongated wires are commonly referred to as “Kirschner wires” or “K-wires”. An example of this is disclosed in U.S. Pat. No. 2,393,694 to Kirschner. The term “bone pin” is more commonly used for shorter structures, such as a length of 2 inches or less, while the term “K-wire” more commonly applies to longer structures, such as a length up to 12 inches, but there is no bright line definition clearly distinguishing between a “bone pin” and a “K-wire” based on length. The present application uses the term “bone wire” to refer to such a small diameter structure and including either a bone pin or a K-wire, regardless of length, but excluding, for instance, a larger diameter bone screw.
Such bone wires have long been used in the orthopaedic arts for several different purposes. Bone wires are often used during surgery as a temporary guide in targeting and directing another more permanent device, such as a cannulated bone screw running over the bone wire, into a bone fragment or anchor bone. Bone wires have been implanted to anchor other devices, such as a bone plate, fixator or external splint device, to a fractured bone. Bone wires have also been used to secure many types of bone fragments to anchor bones, where the term bone “fragment” refers to any part of bone separated by a fracture, regardless of whether that fracture is partial or completely through the bone.
Bone wires commonly have a pointed tip, which may be further fabricated with a drill type structure such that rotation of the bone wire about its longitudinal axis helps to remove bone material from the hole into which the bone wire is advanced. The bone wires may or may not have fine threads to further assist in axially advancing the bone wire into its hole during rotation. While bone wires have been used for fragment fixation, design improvements are needed to have a small diameter bone wire structure which more easily places an appropriate compression force on the interface between the bone fragment and its anchor bone.